<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>练习</title>
    <style>
        div{
            width: 500px;
            height: 500px;
            
            box-sizing: border-box;
            margin: 0 auto;
        }
       #lxx{
           display: none;
       }
    </style>
</head>
<body>
    <div>鼠标移入改变样式，鼠标移除恢复</div>
    <span>我是刘想想</span>
    <div id="lxx">52925959</div>
    <script src="lianxi.js"></script>
</body>
</html>